Association of body mass index and waist circumference with risk of ischemic stroke in adults in China: a prospective cohort study

Abstract

Objective: To explore the relationship between body mass index (BMI), waist circumference (WC) and the risk for ischemic stroke in adults in China. Methods: A total of 36 632 adults were selected from 60 surveillance areas (25 urban surveillance areas and 35 rural surveillance areas) in China Chronic Disease Surveillance Project in 2010 for a follow up study from 2016 to 2017 based on the baseline data in 2010. The follow up was completed for 27 762 adults. Cox proportional hazard regression model was used to analyze the association of body mass index and waist circumference with the risk for ischemic stroke in different populations. The death and hypercholesterolemia cases were excluded by sensitivity analysis. Results: A total of 26 907 adults were included in the analysis. During the follow up period, 1 128 ischemic stroke events were observed (491 in men and 637 in women). After adjusting the related confounding factors and taking normal BMI/normal WC group as the reference, the risk for ischemic stroke increased by 50% in normal BMI/abdominal obesity group (HR=1.50, 95%CI:1.07-2.08), 51% in overweight/abdominal obesity group (HR=1.51, 95%CI:1.20-1.91), 46% in obesity/abdominal obesity group (HR=1.46, 95%CI:1.09-1.96), and 63% in normal BMI/abdominal obesity group (HR=1.63, 95%CI:1.12-2.38), 56% in overweight/abdominal obesity group (HR=1.56, 95%CI: 1.20-2.03) and 45% in obesity/abdominal obesity group (HR=1.45, 95%CI: 1.05-2.01) respectively in men and in men with CVD risk factors. There was no increased risks in the overweight/normal WC group. The risk increased by 40% in overweight/abdominal obesity group (HR=1.40, 95%CI:1.15-1.72) and 46% in obesity/abdominal obesity group (HR=1.46, 95%CI:1.16-1.83), and 35% in overweight/abdominal obesity group (HR=1.35, 95%CI:1.08-1.69) and 30% in obesity/abdominal obesity group (HR=1.30, 95%CI:1.01-1.67) respectively in women and women with CVD risk factors. There were no risk increases in overweight/normal WC group and normal BMI/abdominal obesity group. Sensitivity analysis results showed no change. Conclusion: Overweight/obesity with abdominal obesity or abdominal obesity alone could increase the risk for stroke in men, and overweight/obesity with abdominal obesity could increase the risk for ischemic stroke in women; suggesting that BMI and WC should be used jointly to evaluate obesity in population for weight control to prevent ischemic stroke.